Question: $2.13 \times 0.197 =$
Solution: ${2}$ ${1}$ ${3}$ ${0}$ ${1}$ ${9}$ ${7}$ ${\times\vphantom{0}}$ ${.}$ ${.}$ ${0.03}\times {0.007}= {0.00021}$ ${1}$ ${0.1}\times {0.007}+C{0.0002}= {0.0009}$ ${9}$ ${2}\times {0.007}= {0.014}$ ${4}$ ${1}$ ${0.03}\times {0.09}= {0.0027}$ ${7}$ ${0}$ ${0.1}\times {0.09}+C{0.002}= {0.011}$ ${1}$ ${2}\times {0.09}+C{0.01}= {0.19}$ ${9}$ ${1}$ ${0.03}\times {0.1}= {0.003}$ ${3}$ ${0}$ ${0}$ ${0.1}\times {0.1}= {0.01}$ ${1}$ ${2}\times {0.1}= {0.2}$ ${2}$ ${+\vphantom{0}}$ ${0}$ ${4}$ ${1}$ ${9}$ ${6}$ ${1}$ ${+\vphantom{0}}$ ${0}$ ${4}$ ${1}$ ${9}$ ${6}$ ${1}$ ${+\vphantom{0}}$ ${0}$ ${4}$ ${1}$ ${9}$ ${6}$ ${1}$ ${+\vphantom{0}}$ ${0}$ ${4}$ ${1}$ ${9}$ ${6}$ ${1}$ ${+\vphantom{0}}$ ${0}$ ${4}$ ${1}$ ${9}$ ${6}$ ${1}$ ${.}$ The top number has $2$ digits to the right of the decimal. The bottom number has $3$ digits to the right of the decimal. The product has $2+3=5$ digits to the right of the decimal. $2.13 \times 0.197 = 0.41961$